Method and apparatus for joining ends of wires and the like

ABSTRACT

A method of joining the interfacing ends of cables, one to another, wherein each comprises a plurality of conductor strands, comprising (i) providing each of the ends with an enlarged terminal portion of greater diameter than the cable adjacent the end, (ii) inserting the ends into a connecting tube having an outer layer of an explosive charge, and (iii) detonating the explosive layer so as to compress the connecting tube around the conductor strands. The method offers a cheaper, faster and simpler method of joining a bundle of wires and the like than prior art methods.

FIELD OF THE INVENTION

[0001] The present invention relates to a method for joining wires,rods, cables, high tension lines and the like and for attaching an endfastener thereto, by means of an explosive charge; to said fastener foruse in said method, and to a joined wire fastener combination when madeby said process.

BACKGROUND OF THE INVENTION

[0002] In connection with heavy gauge wires, which may be disposed inpositions which are difficult to reach, commensurately high poweredtools are required to make pressure connections between said wires. Inview of the weight and bulk of the tools it may be inconvenient orimpossible to carry such tools to the sites at which the joining is tobe made.

[0003] It has previously been proposed to connect ends of wires and thelike by inserting the ends into a corresponding bore of a connectingmember provided with an external layer of explosive, which duringdetonation, compresses the connecting member around the ends. The layerof explosive used had, however, an even cross-section along the wholelength thereof in order to produce an even radial compression of theconnecting member.

[0004] In connection with high tension lines, supporting cables and thelike, which are subjected to heavy stresses, it is of great importanceto obtain a permanent, tight clamping effect of the connecting member toensure that no relative sliding movement may occur between the memberand the ends connected thereby.

[0005] Thus, such connectors, herein termed implosive connectors, havebeen used in high energy metalworking to replace conventional hydrauliccompression fittings for high voltage transmission lines. A smallcharge, engineered for each connector, supplies the energy to completethe installation in 1/10,000 of a second, replacing the work of a 60 to100 ton press. Such implosive connectors are completely metallic fittingand result in a void free, uniformly smooth and straight connector.

[0006] In more detail, generally, implosive connectors comprise aconductor splice consisting of an outer aluminum sleeve equipped with apre-mounted implosive charge, and filler, preferably, optionally, aninner steel sleeve having an aluminum tube on the outside.

[0007] However, there remains a need for a method of joining ends ofwires and the like which is cheaper, quicker and easier to install whileproviding at least an acceptable efficacious permanent join of thewires.

SUMMARY OF THE INVENTION

[0008] It is an object of the present invention to provide a method ofjoining ends of wires and the like which is cheaper, faster and easierto effect than prior art methods and apparatus.

[0009] It is a further object to provide a connector for joining ends ofwires and the like of use in the aforesaid method.

[0010] It is a further object of the invention to provide a joined cableassembly comprising a connecting tube and a joined cable when producedby a method as hereinabove defined.

[0011] Accordingly, the invention provides in one aspect, a method ofjoining the interfacing ends of a plurality of wire cables, each cablecomprising a first plurality of conductor strands, said methodcomprising

[0012] (a) providing each of said ends with an enlarged terminal portionof greater diameter than said cable adjacent said end,

[0013] (b) inserting said ends into a connecting tube;

[0014] (c) providing said tube with an outer layer of an explosivecharge, and

[0015] (d) detonating the explosive layer so as to compress theconnecting tube around the conductor strands.

[0016] Preferably, the method as hereinabove defined comprises providingeach of the ends with a terminal enlarging member longitudinally of thecable through the terminal portion to effect the enlargement.

[0017] The enlarging member is most preferably formed of a metal oralloy thereof, e.g. a steel rod insert or an inner sleeve, and, mostpreferably, having a head such as to constitute a stud, cap or the like.

[0018] The terminal portions so abut each other within the connector asto provide a resultant effective joint after the detonation. It can beappreciated that use of a pair of aforesaid flat-headed inserts or capscan enhance the stability and conductivity of such a resultant joint.

[0019] Accordingly, the invention provides in preferred embodiments amethod as hereinabove defined wherein the terminal enlarging member is ametal inner sleeve, which inner sleeve embraces at least one of theconductor strands at an inner location within the plurality of theconductor strands.

[0020] Preferably, the metal sleeve embraces a second plurality of theconductor strands at an inner location within the first plurality ofsaid conductor strands, wherein the second plurality is a portion of thefirst plurality of conductor strands.

[0021] As hereinabove defined, preferably, the metal inner sleeve has aflat head which abuts another flat head, one to another in interfacerelationship within the connecting tube prior and subsequent to thedetonation.

[0022] The second plurality of conductor strands at an inner locationwithin said first plurality of conductor strands are, preferably, formedof steel, while the remainder of the first plurality are formed ofaluminum or alloy thereof.

[0023] Thus, the inner sleeve or cap can embrace a single, but,preferably, a major portion of, and more preferably, all of the secondplurality of the conductor strands. Clearly, the sleeve or cap couldalso further embrace some of the remaining conductor strands whichsurround the second plurality of strands, if desired. Thus, some or allof the outer strands are splayed upon insertion of the sleeve or cap.

[0024] The terminal enlarging member, constituted as a rod or sleevepreferably has a flat head to prevent the member being pushed too farinto the bundle of conductor strands to result in poor abutment of theinterfacing bundle of strands.

[0025] The choice between using a flat headed pin, nail or the like, inpreference to a cap, or vice versa, generally depends on the size of thediameter and strength of the conductor bundle. If a relatively smalldiameter cable, say, for example, of less than 2.5 cm diameter the flatheaded pin is preferred. For a larger diameter and stronger cablebundle, the embracing sleeve or cap is used to account for the largersurface area between the sleeve's cylindrical outer surface and thesurface of the inner core strands, which are generally formed of steel,and to account for the strength of the whole conductor to force out andsplay the outer strands and prevent the inner wire strands from slippingaway.

[0026] It can be readily seen that by increasing the terminal extremitydiameter of the cable relative to the cable adjacent the terminalportions, according to the invention, by means of the inserts, resultsin the cables having a larger diameter than the rest of the conductorinside the sleeve of the connector. Thus, the conductor is so anchoredwithin the sleeve that it cannot disadvantageously slip or be displaced.

[0027] In a most preferred method, the invention provides use of aconnector wherein the explosive layer comprises a first portion ofexplosive and a second portion of explosive, separated therefrom by anintervening interportion distance, wherein each of the first and secondportions is of greater thickness than at interportion distance, andwherein the first and second portions are disposed on the outsidesurface of the connecting tube such that the interportion surrounds eachof the enlarged terminal portions of the ends of the cables; and thefirst and second portions surround the respective cables adjacent theends, prior to detonation, as to effect a greater explosive compactionforce onto the cables adjacent the ends relative to the forces exertedon the terminal portions.

[0028] Thus, in a further feature, the invention provides a connector ashereinabove defined of use in the methods as hereinabove defined.

[0029] In a still further aspect, the invention provides a joined cableassembly comprising a connecting tube and cable resulting from a methodas hereinabove defined.

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order that the invention may be better understood, preferredembodiments will now be described by way of example only with referenceto the accompanying drawings wherein

[0031]FIGS. 1A-1H represent diagrammatic sketches of the components andpreparatory steps practised in a general method of explosively joiningwire ends with a connector, according to the prior art;

[0032]FIGS. 2A-2E represent diagrammatic sketches of the components andpreparatory steps practised in a general method of explosively joiningwire ends with a connector, according to the present invention;

[0033]FIG. 3 is a diagrammatic sketch of a cap within a plurality ofstrands of a cable, according to the invention; and

[0034]FIG. 4 is a diagrammatic longitudinal cross-section of a resultantjoint according to a method and components according to the invention;and wherein the same numerals denote like parts.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0035] With reference to FIGS. 1A and 1B, a conductor splice consists of(a) an outer aluminum cylindrical sleeve (10) having a pre-mountedimplosive charge layer (12) coiled around the outer surface (16) ofconnector (10). Layer (12) is of uniform thickness essentially thelength of surface (16) except at a thicker central portion (18) (FIG.1A); and (b) an inner steel sleeve (20) having an aluminum filter tube(not shown) on the outside (FIG. 1B).

[0036] Operational guidance as given to operators in the field followswith reference to FIGS. 1C-1H.

[0037] 1. Cut conductors (22) as cleanly as possible and minimizeburring or bending aluminum strands (24). Cut steel strands (26) at adistance of half the length of inner steel sleeve (20) less 0.1 in.(2-3mm). Rewind any loose steel strands and bind securely with wire.(FIG. 1C).

[0038] 2. Mark each end of conductors (22) at a distance of half thelength of outer aluminum sleeve (10) less 0.1 (2-3mm). (FIG. 1D).

[0039] 3. Slide the combined charge and aluminum sleeve (10) onto one ofconductor (22) ends. (FIG. 1E).

[0040] 4. Insert steel sleeve (20) into the core of conductor (22) andremove the binding wire. Repeat with the other conductor (22) end andpush both conductors (22) until steel strands (26) meet inner steelsleeve (20). (FIG. 1F).

[0041] 5. Slide the combined charge and aluminum sleeve (10) until eachend of the sleeve corresponds with the marks previously made. (FIG. 1G).

[0042] 6. Mount the assembly and tape the detonator securely at theindicated position on the implosive sleeve (FIG. 1H). Before initiation,ensure that outside aluminum sleeve (10) is correctly positioned withconductors (22). (FIG. 1H).

[0043] 7. Effect initiation and detonation.

[0044] With reference to FIGS. 2A-2E, the conductor splice of use in thepresent invention consists of an outer aluminum sleeve (100) shown inFIG. 2A equipped with a pre-mounted implosive charge (102), wherein theamount of implosive charge is approx. 20-25% less than the aforesaidprior art embodiment of FIG. 1A and a pair of studs (104) steel insert(FIG. 2B).

[0045] In instructional format, the operational steps are as follows.

[0046] Cut conductors (22) as cleanly as possible. Push steel stud (104)through the center of conductor (22) at the end thereof until thealuminum head of stud (104) rests against the conductor (FIGS. 2C and2D) and provides an enlarged terminal portion (106).

[0047] Insert both conductors (22) inside the implosive aluminum sleeve(100), one on each side, until they abut at the center of sleeve (100)(FIG. 2E).

[0048] Main sleeve (100) has a layer of explosive cord (102) ofessentially uniform thickness along the length of sleeve (100), exceptat a first portion (108) and a second portion (110) displaced from themiddle of sleeve (100) as to provide an intervening interportiondistance (112) which interportion layer of explosive surrounds each ofthe enlarged terminal portions (106). Each of first and second explosivelayers at portions (108) and (110) has a greater thickness than at saidinterportion distance, and wherein said first and second portions aredisposed on the outside surface of said connecting tube such that saidinterportion surrounds each of said enlarged terminal portions of saidends of said cables and said first and second portion surround saidcables adjacent said ends, prior to said detonation, as to effect agreater explosive compaction force onto said cables adjacent said endsrelative to the forces exerted on said terminal portions.

[0049] The explosive is initiated as an implosive charge as for priorart embodiments.

[0050]FIG. 3 shows a cap 150 having a head 152 partly inserted intocable 22 to surround an inner of streel strands 154 and surrounded byouter aluminum strands 156. The arrow indicates the direction that cap150 is to be moved to be fully inserted into cable 22

[0051]FIG. 4 is a diagrammatic longitudinal cross-section of a resultantjoin according to a method and components according to the invention.

[0052] It can, thus, be readily seen that most advantageously only asingle connector, sleeve or the like need be used to provide a mostefficacious joint, in a faster and cheaper manner than the prior artmethods, while providing a non-slip product.

[0053] Although this disclosure has described and illustrated certainpreferred embodiments of the invention, it is to be understood that theinvention is not restricted to those particular embodiments. Rather, theinvention includes all embodiments which are functional or mechanicalequivalents of the specific embodiments and features that have beendescribed and illustrated.

1. A method of joining the interfacing ends of cables, one to another,each cable comprising a first plurality of conductor strands, saidmethod comprising (a) providing each of said ends with an enlargedterminal portion of greater diameter than said cable adjacent said end;(b) inserting said ends into a connecting tube; (c) providing said tubewith an outer layer of an explosive charge, and (d) detonating theexplosive layer so as to compress the connecting tube around theconductor strands.
 2. A method as defined in claim 1 comprisingproviding said ends with a terminal enlarging member longitudinally ofsaid cable through said terminal portion to effect said enlargement. 3.A method as defined in claim 2 wherein said enlarging member is a metalrod.
 4. A method as defined in claim 3 wherein said metal rod has a flathead.
 5. A method as defined in claim 4 wherein said flat heads abut oneto another within said connecting tube prior to said detonation.
 6. Amethod as defined in claim 2 wherein said terminal enlarging member is ametal inner sleeve, which inner sleeve embraces at least one of saidconductor strands at an inner location within said plurality of saidconductor strands.
 7. A method as defined in claim 6 wherein said metalsleeve embraces a second plurality of said conductor strands at an innerlocation within said first plurality of said conductor strands, whereinsaid second plurality is a portion of said first plurality of conductorstrands.
 8. A method as defined in claim 6 wherein said metal sleeve hasa flat head.
 9. A method as defined in claim 7 wherein said metal sleevehas a flat head.
 10. A method as defined in claim 8 wherein said flatheads abut one to another within said connecting tube prior to saiddetonation.
 11. A method as defined in claim 9 wherein said flat headsabut one to another within said connecting tube prior to saiddetonation.
 12. A method as defined in claim 7 wherein said secondplurality of conductor strands at an inner location within said firstplurality of conductor strands are formed of steel, while the remainderof said first plurality are formed of aluminum or alloy thereof.
 13. Amethod as defined in claim 1 wherein said explosive layer comprises afirst portion of explosive and a second portion of explosive separatedtherefrom by an intervening interportion distance, wherein each of saidfirst and second portions has a greater thickness than at saidinterportion distance, and wherein said first and second portions aredisposed on the outside surface of said connecting tube such that saidinterportion surrounds each of said enlarged terminal portions of saidends of said cables and said first and second portion surround saidcables adjacent said ends, prior to said detonation, as to effect agreater explosive compaction force onto said cables adjacent said endsrelative to the forces exerted on said terminal portions.
 14. Aconnector comprising a connecting tube and a layer of explosive asdefined in claim
 13. 15. A joined cable assembly comprising a connectingtube and a joined cable when produced by a method as defined in claim 1.16. A joined cable assembly comprising a connecting tube and a joinedcable when produced by a method as defined in claim
 2. 17. A joinedcable assembly comprising a connecting tube and a joined cable whenproduced by a method as defined in claim
 4. 18. A joined cable assemblycomprising a connecting tube and a joined cable when produced by amethod as defined in claim
 7. 19. A joined cable assembly comprising aconnecting tube and a joined cable when produced by a method as definedin claim
 8. 20. A joined cable assembly comprising a connecting tube anda joined cable when produced by a method as defined in claim 12.